Re: Are there different types of acid in vinegar, coca-cola and orange juice?

Yes, each of these drinks contains a different acid as its major component:

Vinegar - Acetic acid

Coca-cola® - Carbonic acid

also contains citric acid and phosphoric acid

Orange Juice - Citric acid

There are some important observations to mention. The concentrations (relative amounts) of each solution are different, as are the amounts of other chemicals, like the bases you mentioned, in each. For instance, vinegar is almost pure, dilute acetic acid, while orange juice contains sugars, proteins, vitamins, and a slew of other chemicals that all affect its acidity. Also, the brown color on the Coca-cola® egg probably would not have been seen if you'd used an undyed carbonated beverage, like 7-UP® or even seltzer. It might even be interesting to compare the effects of Coca-cola® straight out of the can versus Coca-cola® that's had a chance to go "flat". Ideally, if your teacher had some pH-paper (or even a pH-meter!), you could compare the effects on the eggs with the actual acidity of the solution.